Caroline Herschel - Astronomical Work

Astronomical Work

William's interest in astronomy started as a hobby to pass time at night. At breakfast the next day he would give an impromptu lecture on what he had learned the night before. Caroline became as interested as William, stating that she was "much hindered in my practice by my help being continually wanted in the execution of the various astronomical contrivances." William became known for his work on high performance telescopes, and Caroline found herself supporting his efforts.

In 1782, William accepted the office of King's Astronomer to George III and moved to Datchet and subsequently to Observatory House near Slough (then in Buckinghamshire, now in Berkshire). The new job proved to be a mixed blessing; although it left him with ample free time to continue his astronomical observations, it also meant a reduction in income and being called upon by the king for entertainment at any time. During this time William perfected his telescope making, building a series of ever larger devices that ultimately ended with his famous 40-foot (12 m) focal length instrument. Caroline was his constant assistant in his observations, also performing the laborious calculations with which they were connected. During one such observation run on the large telescope in 1783, Caroline became caught on an iron hook and when she was helped off "...they could not lift me without leaving nearly 2 ounces of my flesh behind."

During her leisure hours she occupied herself with observing the sky with a 27-inch (690 mm) focal length Newtonian telescope and by this means detected a number of astronomical objects during the years 1783 – 87, including most notably an independent discovery of M110 (NGC 205), the second companion of the Andromeda Galaxy. During 1786 – 97 she also discovered eight comets, her first comet being discovered on 1 August 1786. She had unquestioned priority on five of the comets and had rediscovered Comet Encke in 1795. In 1787, she was granted an annual salary of £50 by George III for her work as William's assistant.

In 1797 William's observations had shown that there were a great many discrepancies in the star catalogue published by John Flamsteed, which was difficult to use due to its having been published as two volumes, the catalogue proper and a volume of original observations. William realised that he needed a proper cross-index in order to properly explore these differences but was reluctant to devote time to it at the expense of his more interesting astronomical activities. He therefore recommended to Caroline that she undertake the task. The resulting Catalogue of Stars was published by the Royal Society in 1798 and contained an index of every observation of every star made by Flamsteed, a list of errata, and a list of more than 560 stars that had not been included.

Caroline returned to Hanover in 1822 following her brother's death, but did not abandon her astronomical studies, continuing to verify and confirm William's findings and producing a catalogue of nebulae to assist her nephew John Herschel in his work. In 1828 the Royal Astronomical Society presented her with their Gold Medal for this work — no woman would be awarded it again until Vera Rubin in 1996.

In 1835, along with Mary Somerville, she was elected to honorary membership of the Royal Astronomical Society; they were the first honorary women members. In 1838 she was also elected as a member of the Royal Irish Academy. In 1846, at the age of 96, she was awarded the Gold Medal for Science by the King of Prussia.

Caroline Herschel died at Hanover on 9 January 1848. She is buried at 35 Marienstrasse in Hanover at the cemetery of the Gartengemeinde.